For labeling containers, such as beverage bottles or the like, it is known, for example, from DE 20 2012 003 268 U1, to first separate sheet-shaped labels from a label strip in a cutting unit provided endlessly from a reel and to suction them at a continuously rotating vacuum transfer cylinder for subsequent transfer of the labels to containers and to apply glue to them during circulation. Switchable suction bars are formed on the vacuum transfer cylinder for the lateral front and end areas of the labels. They are selectively switchable from an outer working position, in which the suction bars guide a label area held by them against a gluing unit present in the periphery of the vacuum transfer cylinder, to an inner passing position in which they do not contact the gluing unit.
In particular in production systems in which the individual processing machines are formed to be mechanically firmly interconnected, position gaps inevitably occur in the incoming flow of containers due to errors upstream of the labeling machine. Since the vacuum transfer cylinder rotates continuously during operation, a position gap must also be generated in the flow of labels at the conveying position corresponding to the position gap of the flow of containers, in that the vacuum transfer cylinder is not provided with a label at the respective slot. Consequently, the empty suctions bars are exposed when passing the gluing unit and must be switched to the inner passing position to avoid glue being applied to the suction bars.
For switching the suction bars, preferably a stationary switching unit with displaceable operating cams, which interact with the control rollers coupled to the suction bars and switch them to the inner position, is present below the vacuum transfer cylinder. A roller mechanism for switching the operating cams is typically available In the switching unit. It needs to, firstly, switch rapidly and, secondly, transmit comparatively high switching forces. This causes loud switching noise and undesirable high wear of the switching mechanism.
Therefore, a need exists for a labeling unit which is improved in this respect and a labeling method which enables correspondingly improved machine operation when position gaps occur in the flow of containers.